The response to the message was immediate and electric.
It was quickly amplified by prominent Trump supporters with influential followings, like Alex Jones, the impresario of the conspiracy-laden media outlet Infowars, and the right-wing podcaster Tim Pool.
In the darkest corners of the internet, Trump supporters on websites such as TheDonald.win soon began discussing bringing handcuffs, body armor, shields, bats and pepper spray to Washington. Others talked about committing violence.
“Why don’t we just kill them?” one person wrote on the chat board 4chan. “Every last democrat, down to the last man, woman, and child?”
Mr. Trump’s tweet also had significant effects in the real world.
Within days of it being posted, a pro-Trump organizing group called Women for America First changed its plans to hold a rally in Washington after Mr. Biden’s inauguration, moving the event up to Jan. 6. Around the same time, the committee showed, the prominent Stop the Steal organizer Ali Alexander registered the website WildProtest.com, which provided information about numerous protests in Washington on Jan. 6 with event times, places, speakers and details on transportation.
Mr. Alexander sent a text to an associate on Jan. 5, 2021, saying that he believed Mr. Trump was going to “order” him and his associates to march to the Capitol, the committee showed.
On Dec. 21, 2020 — two days after Mr. Trump’s tweet about Jan. 6 was posted — a group of far-right members of Congress met with the president at the White House to discuss the conservative lawyer John Eastman’s theories about pressuring Mr. Pence to disrupt the normal workings of the Electoral College and keep Mr. Trump in power. The members of Congress at the meeting included Representatives Andy Biggs of Arizona, Matt Gaetz of Florida, Louie Gohmert of Texas and Scott Perry of Pennsylvania, the committee said.